Usefulness of ECG criteria to rule out left ventricular hypertrophy in older individuals with true left bundle branch block: an observational study.

BACKGROUND: Advanced age is associated with both left bundle branch block (LBBB) and hypertension and the usefulness of ECG criteria to detect left ventricular hypertrophy (LVH) in patients with LBBB is still unclear. The diagnostic performance and clinical applicability of ECG-based LVH criteria in patients with LBBB defined by stricter ECG criteria is unknown. The aim of this study was to compare diagnostic accuracy and clinical utility of ECG criteria in patients with advanced age and strict LBBB criteria. METHODS: Retrospective single-center study conducted from Jan/2017 to Mar/2018. Patients undergoing both ECG and echocardiogram examinations were included. Ten criteria for ECG-based LVH were compared using LVH defined by the echocardiogram as the gold standard. Sensitivity, specificity, predictive values, likelihood ratios, AUC, and the Brier score were used to compare diagnostic performance and a decision curve analysis was performed. RESULTS: From 4621 screened patients, 68 were included, median age was 78.4 years, (IQR 73.3-83.4), 73.5% with hypertension. All ECG criteria failed to provide accurate discrimination of LVH with AUC range between 0.54 and 0.67, and no ECG criteria had a balanced tradeoff between sensitivity and specificity. No ECG criteria consistently improved the net benefit compared to the strategy of performing routine echocardiogram in all patients in the decision curve analysis within the 10-60% probability threshold range. CONCLUSION: ECG-based criteria for LVH in patients with advanced age and true LBBB lack diagnostic accuracy or clinical usefulness and should not be routinely assessed.

Exercise-induced quantitative microvolt T-wave alternans in hypertrophic cardiomyopathy.

BACKGROUND/PURPOSE: Patients with hypertrophic cardiomyopathy (HCM) have elevated risk for sudden cardiac death (SCD). Our study aimed to quantitatively characterize microvolt T-wave alternans (TWA), a potential arrhythmia risk stratification tool, in this HCM patient population. METHODS: TWA was analyzed with the quantitative modified moving average (MMA) in 132 HCM patients undergoing treadmill exercise testing, grouped according to Maron score risk factors as high-risk (H-Risk, n=67,), or low-risk (L-Risk, n=65, without these risk factors). RESULTS: TWA levels were much higher for the H-Risk than for the L-Risk group (101.40±75.61 vs. 54.35±46.26µV; p<0.0001). A 53µV cut point, set by receiver operator characteristic (ROC), identified H-Risk patients (82% sensitivity, 69% specificity). CONCLUSIONS: High TWA levels were found for hypertrophic cardiomyopathy patients. Abnormal TWA associated with major risk factors for SCD: non-sustained ventricular tachycardia on Holter (p=0.001), family history of SCD (p=0.006), septal thickness ≥30mm (p<0.001); and inadequate blood pressure response to effort (p=0.04).

Controversial and similar aspects of the Brugada and J wave patterns: The vectorcardiogram point of view-Revision 2.

BACKGROUND: The J-wave electrocardiographic patterns include early repolarization (ER) and Brugada syndrome; especially when ER is located in the anteroseptal leads (V1-V3), it can mimic the Brugada syndrome (BrS) ECG pattern and therefore mislead the diagnosis. We aimed to define the vectorcardiographic characteristics of BrS and ER using aspects of QRS complex loop, J-point and ST-segment. METHODS/RESULTS: Vectorcardiographic loops in the transverse plane (TP) of 14 BrS patients and 26 individuals with ER were analyzed and defined, and then a third group of 17 patients with non-characteristic ECG patterns were analyzed and compared with them. All QRS loops showed end-conduction delay (ECD) located in the right posterior-anterior quadrant (BrS) or left posterior-anterior quadrant (ER). In 100% cases a "break" in the QRS loop end, resembling a "nose" identified BrS, and a "fish-hook" shape identified ER. Non-coincidental QRS complex onset-end defined J-point resulting vector. BrS showed a significantly longer end-conduction delay (100% right anterior quadrant), shorter J-point amplitude oriented to the right, and "nose-like" QRS end loop. Analysis of group 3 confirmed the accuracy of the qualitative aspects to distinguish this "atypical" population: "fish-hook" shape of ER in the transverse plane in 6 individuals; and the "nose" shape of BrS in 14 patients, among which 2 patients had both patterns simultaneously. CONCLUSIONS: Vectorcardiographic characteristics could clearly differentiate BrS from ER qualitatively and quantitatively even in atypical ECGs.

Rare Association: Chagas' Disease and Hypertrophic Cardiomyopathy.

A woman (49 years) with Chagas' disease showed: ECG, right bundle-branch block and left anterior-superior fascicular block; V1 has unusual R > R', and elevated ST segment from V2 to V6 . Additional imaging revealed concomitant HCM and Chagas, which is uncommon. Overlapping of ECG findings can be explained by this rare association of diseases.

Prognostic Evaluation of Microvolt T-Wave Alternans in Hypertrophic Cardiomyopathy: 9-year Clinical Follow-up. / Avaliação Prognóstica da Microalternância da onda T na Cardiomiopatia Hipertrófica em um Seguimento Clínico de 9 anos.

BACKGROUND: Sudden cardiac death (SCD) resulting from ventricular arrhythmia is the main complication of hypertrophic cardiomyopathy (HCM). Microvolt T-wave alternans (MTWA) is associated with the occurrence of ventricular arrhythmias in several heart diseases, but its role in HCM remains uncertain. OBJECTIVE: To evaluate the association of MTWA with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients in a long-term follow-up. METHODS: Patients diagnosed with HCM and NYHA functional class I-II were consecutively selected. At the beginning of the follow-up, the participants performed the MTWA evaluation using the modified moving average during the stress test. The results were classified as altered or normal. The composite endpoint of SCD, ventricular fibrillation, sustained ventricular tachycardia (SVT) or appropriate implantable cardiac defibrillation (ICD) therapy was assessed. The level of significance was set at 5%. RESULTS: A total of 132 patients (mean age of 39.5 ± 12.6 years) were recruited and followed for a mean of 9.5 years. The MTWA test was altered in 74 (56%) participants and normal in 58 (44%). Nine events (6.8%) occurred during the follow-up, with a prevalence of 1.0%/year - six SCDs, two appropriate ICD shocks and one episode of (SVT). Altered MTWA was associated with non-sustained ventricular tachycardia on Holter (p = 0.016), septal thickness ≥30 mm (p < 0.001) and inadequate blood pressure response to effort (p = 0.046). Five patients with altered MTWA (7%) and four patients with normal MTWA (7%) had the primary outcome [OR = 0.85 (95% CI: 0.21 - 3.35, p=0.83)]. Kaplan-Meir event curves showed no differences between normal and altered MTWA. CONCLUSION: Altered MTWA was not associated with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients, and the low rate of these events during long-term follow-up suggests the good prognosis of this heart disease.

FUNDAMENTO: A morte súbita cardíaca (MSC), decorrente de arritmias ventriculares, é a principal complicação da cardiomiopatia hipertrófica (CMH). A microalternância da onda T (MAOT) está associada à ocorrência de arritmias ventriculares em diversas cardiopatias, mas seu papel na CMH permanece incerto. OBJETIVO: Avaliar associação da MAOT com a ocorrência de MSC ou arritmias ventriculares malignas em pacientes com CMH. MÉTODO: Pacientes com diagnóstico de CMH e classe funcional I-II (NYHA) foram selecionados de forma consecutiva. No início do seguimento os participantes realizaram a avaliação da MAOT pela metodologia da média móvel modificada no teste de esforço. Os resultados foram classificados em alterado ou normal. O desfecho foi composto por MSC, fibrilação ventricular, taquicardia ventricular sustentada (TVS) e terapia apropriada do cardioversor desfibrilador implantável (CDI). O nível de significância estatística foi de 5%. RESULTADOS: Um total de 132 pacientes (idade média de 39,5±12,6 anos) foram incluídos, com tempo de seguimento médio de 9,5 anos. A MAOT foi alterada em 74 (56%) participantes e normal em 58 (44%). Durante o seguimento, nove (6,8%) desfechos ocorreram, com prevalência de 1,0%/ano, sendo seis casos de MSC, dois choques apropriados do CDI e um episódio de TVS. MAOT alterada foi associada à taquicardia ventricular não sustentada no Holter (p=0,016), espessura septal≥30 mm (p<0,001) e resposta inadequada da pressão arterial ao esforço (p=0,046). Cinco pacientes (7%) e quatro pacientes (7%) com MAOT alterada e normal, respectivamente, apresentaram desfecho primário [OR=0,85(IC95%: 0,21­3,35, p=0,83)]. Curvas de eventos de Kaplan-Meir não apresentaram diferenças entre MAOT normal e alterada. CONCLUSÃO: A MAOT alterada não foi associada à ocorrência de MSC ou arritmias ventriculares potencialmente fatais em pacientes com CMH, e a baixa taxa desses eventos em um seguimento em longo prazo sugere o bom prognóstico dessa cardiopatia.

Electrovectorcardiographic study of left ventricular aneurysm in ischemic heart disease.

The aim was to characterize the electrovectorcardiographic pattern of ventricular aneurysms in ischemic cardiopathy by analyzing the cardiac ventricular repolarization. The medical records of 2,670 individuals were analyzed in this cross-sectional study. A test phase included 33 patients who underwent transthoracic echocardiogram with ultrasonic enhancing agent, electrocardiogram, and vectorcardiogram (aneurysm group - n = 22, and akinesia group - n = 11). In the validation phase, cardiac magnetic resonance imaging established the left ventricle segmental contractility in 16 patients who underwent electrocardiographic and vectorcardiographic tests (aneurysm group, n = 8, and akinesia group, n = 8). The variables studied were the presence of the T-wave plus-minus pattern and the T-wave loop anterior-posterior pattern in V2-V4. The diagnostic indices used were sensitivity, specificity, and predictive values, with their respective 95% confidence intervals. During the test and validation phases, the analysis of the presence of the T-wave plus-minus pattern identified the aneurysm group with a sensitivity of 91% vs. 87% and specificity of 91% vs. 87% (p < 0.0001 vs. p = 0.01), respectively. Meanwhile, the T-wave loop anterior-posterior pattern evidenced sensitivity of 95% vs. 77% and specificity of 91% vs. 87% (p < 0.0001 vs. p = 0.04), respectively. The electrovectorcardiographic parameters showed high accuracy for recognizing left ventricular aneurysms in ischemic heart disease.

A study of effectiveness of midazolam sedation for prevention of myocardial arrhythmias in endosseous implant placement.

PURPOSE: The study aimed to assess electrocardiographic alterations during oral implant placement surgeries under local anesthesia (lidocaine chlorhydrate with epinephrine), using 15 mg of midazolam as an anxiolytic premedication. MATERIAL AND METHODS: The study randomly selected 20 patients, aged 21-50 years old, requiring bilateral mandibular dental implants. Each patient was assessed using placebo on one side and midazolam on the contralateral side, with random, double-blinded distribution. The electrocardiogram recorded 12 static leads every 2 min, while D2 derivations were recorded continuously. RESULTS: No statistically significant differences were observed between the placebo and midazolam when analyzing the morphological behavior of the electrocardiographic wave and the presence of arrhythmias during the experiment. However, under sedation, assessment of the behavior of electrocardiographic parameters during different stages of the procedure revealed statistically significant differences (P<0.05) for heart rate, P-wave amplitude and duration of the RR and QTc intervals. The arrhythmias detected were considered low risk for patients without systemic alterations and were observed in 53.3% of patients. The most frequently occurring alterations were tachycardia, bradycardia, supraventricular and ventricular extrasystoles and blocked atrial extrasystole, which were similar for both placebo and midazolam, with the greatest incidence during the initial, incision and bone drilling stages. CONCLUSION: The use of 15 mg of midazolam made no difference compared with the placebo. The use of 15 mg of midazolam did not show an advantage in the incidence of arrhythmias The anxiolytic premedication does not prevent myocardial arrhythmias in endosseous implant placement. The clinical significance of the arrhythmias may not represent serious risks.

Electrocardiographic Evaluation of Normal Newborns in the First Week of Life - Observational Study. / Avaliação Eletrocardiográfica de Recém-Nascidos Normais na Primeira Semana de Vida ­ Estudo Observacional.

BACKGROUND: The neonatal period is marked by major changes in the cardiovascular system, especially in the first week of life. Unlike the adult population, studies on electrocardiogram (ECG) data in the neonatal period are scarce. This is the first study to describe electrocardiographic changes in a cohort of newborns with normal echocardiograms. OBJECTIVES: To analyze the electrocardiographic patterns of a population of full-term NB, without any cardiac morphological or functional anomalies, and compare the results with the literature. METHODS: In this observational study, echocardiograms and ECG results from 94 newborns divided in three age groups (up to 24 hours, between 25 and 72 hours, and between 73 and 168 hours of life) were evaluated and compared with those reported by Davignon et al. A p-value <0.05 was considered statistically significant. RESULTS: There were significant differences in T-wave direction in leads V1 (p= 0.04), V2 (p= 0.02), V3 (p= 0.008) and V4 (p= 0.005) between the three age groups. There were differences between our findings and the current literature in most of the parameters. CONCLUSION: Term newborns within 24 hours of life showed significantly more positive T waves than older ones. Many differences from the Davignon's ECG parameters were found, particularly in the P, Q, R, S amplitudes, QRS duration, R/S and R+S. These findings indicate that more studies are needed for a definitive interpretation of the ECG in newborns.

FUNDAMENTO: O período neonatal é marcado por muitas alterações importantes no sistema cardiovascular, principalmente na primeira semana de vida. Diferentemente da população adulta, estudos sobre dados de eletrocardiograma (ECG) no período neonatal são escassos. Este é o primeiro estudo a descrever alterações eletrocardiográficas em uma coorte de recém-nascidos com ecocardiogramas normais. OBJETIVOS: Analisar padrões eletrocardiográficos de uma população de recém-nascidos a termo, sem anomalias morfológicas ou funcionais cardíacas, e comparar os resultados com a literatura. MÉTODOS: Neste estudo observacional, ecocardiogramas e resultados de ECG de 94 neonatos divididos em três grupos etários (até 24 horas, entre 25 e 72 horas, e entre 73 e 168 horas de vida) foram avaliados e comparados com aqueles descritos por Davignon et al. Um valor de p < 0,05 foi considerado estatisticamente significativo. RESULTADOS: Diferenças significativas na direção da onda T foram detectadas nas derivações V1 (p= 0,04), V2 (p= 0,02), V3 (p= 0,008) e V4 (p= 0,005). Houve diferenças entre nossos resultados e a literatura atual na maioria dos parâmetros. CONCLUSÃO: Recém-nascidos a termo com menos de 24 horas de vida apresentaram significativamente mais ondas T positivas que aqueles com mais horas de vida. Encontramos muitas diferenças nos parâmetros de ECG em comparação aos descritos por Davignon et al., particularmente nas amplitudes de P, Q, R, S, duração do QRS, R/S e R+S. Esses achados indicam a necessidade de mais estudos para uma interpretação definitiva do ECG em recém-nascidos.

Modified moving average methodology applied to the treadmill stress testing analysis of microvolt T-wave alternans.

Sudden cardiac death is impactful. There has been an increase in the search for tools capable of identifying individuals who are most susceptible, such as the microvolt T-wave alternans. This study aims to analyze the applicability of the modified moving average methodology to obtain the microvolt T-wave alternans using treadmill specific protocols. Medical records of patients during the period August 2006-December 2014 were retrospectively analyzed. Five hundred and thirty nine exams were then included, divided into groups according to the protocol and updating factor used: Ellestad factor 8 or 32, Naughton factor 8 or 32. The topics for analysis were the alternans behavior, noise and confirmation according to the groups of leads analyzed (frontal, transversal and orthogonal planes). The greater microvolt T-wave alternans was found during the stress phase in most of the tests. Group Naughton 8 presented lower noise in this phase for the transverse and orthogonal planes (p = 0.0082 and p < 0.0001), with greater confirmation of frontal and orthogonal planes in comparison with group Ellestad 8 (p = 0.0002 and 0.0008). The results indicate the viability of simultaneous performance of the stress test and measurement of the T wave alternans with Naughton protocol with 1/8 updating factor.

Characterization of the electrocardiographic pattern of individuals with cerebral palsy.

BACKGROUND: Dentists of Lar São Francisco observed during dental treatment that children with cerebral palsy (CP) had increased heart rate (HR) and lower production of saliva. Despite the high prevalence of CP found in the literature (2.08-3.6/1000 individuals), little is known about the electrocardiographic (ECG) characteristics, especially HR, of individuals with CP. OBJECTIVE: This study aimed to investigate the hypothesis that individuals with CP have a higher HR and to define other ECG characteristics of this population. METHODS: Ninety children with CP underwent clinical examination and 12-lead rest ECG. Electrocardiographic data on rhythm, HR, PR interval, QRS duration, P/QRS/T axis, and QT, QTc and T(peak-end) intervals (minimum, mean, maximum, and dispersion) were measured and analyzed then compared with data from a control group with 35 normal children. Fisher and Mann-Whitney U tests were used, respectively, to compare categorical and continuous data. RESULTS: Groups cerebral palsy and control did not significantly differ in age (9 ± 3 × 9 ± 4 years) and male gender (65% × 49%). Children with CP had a higher HR (104.0 ± 20.6 × 84.2 ± 13.3 beats per minute; P < .0001), shorter PR interval (128.8 ± 15.0 × 138.1 ± 15.1 milliseconds; P = .0018), shorter QRS duration (77.4 ± 8.6 × 82.0 ± 8.7 milliseconds; P = .0180), QRS axis (46.0° ± 26.3° × 59.7° ± 24.8°; P = .0024) and T-wave axis (34.3° ± 28.9° × 42.9° ± 17.1°; P = .034) more horizontally positioned, and greater mean QTc (418.1 ± 18.4 × 408.5 ± 19.4 milliseconds; P = .0110). All the electrocardiogram variables were within the reference range for the age group including those with significant differences. CONCLUSION: Children with CP showed increased HR and other abnormal ECG findings in the setting of this investigation. Further studies are needed to explain our findings and to correlate the increased HR with situations such as dehydration, stress, and autonomic nervous disorders.

Andersen-Tawil Syndrome: A Comprehensive Review.

Andersen-Tawil syndrome (ATS) is a very rare orphan genetic multisystem channelopathy without structural heart disease (with rare exceptions). ATS type 1 is inherited in an autosomal dominant fashion and is caused by mutations in the KCNJ2 gene, which encodes the α subunit of the K+ channel protein Kir2.1 (in ≈ 50-60% of cases). ATS type 2 is in turn linked to a rare mutation in the KCNJ5-GIRK4 gene that encodes the G protein-sensitive-activated inwardly rectifying K+ channel Kir3.4 (15%), which carries the acetylcholine-induced potassium current. About 30% of cases are de novo/sporadic, suggesting that additional as-yet unidentified genes also cause the disorder. A triad of periodic muscle paralysis, repolarization changes in the electrocardiogram, and structural body changes characterize ATS. The typical muscular change is episodic flaccid muscle weakness. Prolongation of the QU/QUc intervals and normal or minimally prolonged QT/QTc intervals with a tendency to ventricular arrhythmias are typical repolarization changes. Bidirectional ventricular tachycardia is the hallmark ventricular arrhythmia, but also premature ventricular contractions, and rarely, polymorphic ventricular tachycardia of torsade de pointes type may be present. Patients with ATS have characteristic physical developmental dysmorphisms that affect the face, skull, limbs, thorax, and stature. Mild learning difficulties and a distinct neurocognitive phenotype (deficits in executive function and abstract reasoning) have been described. About 60% of affected individuals have all features of the major triad. The purpose of this review is to present historical aspects, nomenclature (observations/criticisms), epidemiology, genetics, electrocardiography, arrhythmias, electrophysiological mechanisms, diagnostic criteria/clues of periodic paralysis, prognosis, and management of ATS.

Clinical applicability and diagnostic performance of electrocardiographic criteria for left ventricular hypertrophy diagnosis in older adults.

Recently, a new ECG criterion, the Peguero-Lo Presti (PLP), improved overall accuracy in the diagnosis of left ventricular hypertrophy (LVH)-compared to traditional ECG criteria, but with few patients with advanced age. We analyzed patients with older age and examined which ECG criteria would have better overall performance. A total of 592 patients were included (83.1% with hypertension, mean age of 77.5 years) and the PLP criterion was compared against Cornell voltage (CV), Sokolow-Lyon voltage (SL) and Romhilt-Estes criteria (cutoffs of 4 and 5 points, RE4 and RE5, respectively) using LVH defined by the echocardiogram as the gold standard. The PLP had higher AUC than the CV, RE and SL (respectively, 0.70 vs 0.66 vs 0.64 vs 0.67), increased sensitivity compared with the SL, CV and RE5 (respectively, 51.9% [95% CI 45.4-58.3%] vs 28.2% [95% CI 22.6-34.4%], p < 0.0001; vs 35.3% [95% CI 29.2-41.7%], p < 0.0001; vs 44.4% [95% CI 38.0-50.9%], p = 0.042), highest F1 score (58.3%) and net benefit for most of the 20-60% threshold range in the decision curve analysis. Overall, despite the best diagnostic performance in older patients, the PLP criterion cannot rule out LVH consistently but can potentially be used to guide clinical decision for echocardiogram ordering in low-resource settings.

Ventricular repolarization abnormalities: the electrocardiographic track of cardiac tumoural involvement in an infant with tuberous sclerosis complex. A case report.

BACKGROUND: Primary cardiac tumours are rare in children. Against this backdrop, Doppler echocardiogram is the main diagnostic procedure, while electrocardiogram (ECG) usually plays a secondary role, by detecting tumoural consequences as cardiac arrhythmias and chambers overload. We describe a case where an electrocardiographic sign was the cornerstone to diagnosis and surveillance of an infant with a cardiac rhabdomyoma. CASE SUMMARY: A female infant was referred for cardiac evaluation to elucidate an electrocardiographic abnormality, detected during investigation of seizures. She had recently been diagnosed with epilepsy and was under three different anticonvulsants for appropriate control. Cardiovascular symptoms were absent. Skin inspection revealed hypochromic macules. Respiratory and cardiovascular examinations were normal, as well as laboratorial tests and chest radiography. Electrocardiogram (ECG) showed dome-shaped ST-segment elevation in V2 and V3. Transthoracic echocardiogram unveiled a single hyper-echogenic node (0.4 cm2) in the interventricular septum. Cardiac chambers had normal size and function and Doppler analysis was also normal. No specific medication was used to treat the tumour. During follow-up, she remained free of cardiac symptoms. Eighteen months after her first visit to the cardiologist, routine clinical assessment, ECG, and transthoracic Doppler echocardiogram normal results stated the spontaneous and complete involution of the tumoural lesion. DISCUSSION: Convex ST-segment elevation, generally related to myocardial injury, is unusual in paediatric patients. Once it occurs in asymptomatic individuals within this age bracket, exclusion of cardiac tumours is mandatory. However, data regarding the accuracy of such electrocardiographic marker in this clinical setting are still to be defined.

Comparison of quantitative T-wave alternans profiles of healthy subjects and ICD patients.

BACKGROUND: Current relevance of T-wave alternans is based on its association with electrical disorder and elevated cardiac risk. Quantitative reports would improve understanding on TWA augmentation mechanisms during mental stress or prior to tachyarrhythmias. However, little information is available about quantitative TWA values in clinical populations. This study aims to create and compare TWA profiles of healthy subjects and ICD patients, evaluated on treadmill stress protocols. METHODS: Apparently healthy subjects, not in use of any medication were recruited. All eligible ICD patients were capable of performing an attenuated stress test. TWA analysis was performed during a 15-lead treadmill test. The derived comparative profile consisted of TWA amplitude and its associated heart rate, at rest (baseline) and at peak TWA value. Chi-square or Mann-Whitney tests were used with p values < or = 0.05. Discriminatory performance was evaluated by a binary logistic regression model. RESULTS: 31 healthy subjects (8F, 23M) and 32 ICD patients (10F, 22M) were different on baseline TWA (1 +/- 2 microV; 8 +/- 9 muV; p < 0.001) and peak TWA values (26 +/- 13 microV; 37 +/- 20 microV; p = 0,009) as well as on baseline TWA heart rate (79 +/- 10 bpm; 67 +/- 15 bpm; p < 0.001) and peak TWA heart rate (118 +/- 8 bpm; 90 +/- 17 bpm; p < 0.001). The logistic model yielded sensitivity and specificity values of 88.9% and 92.9%, respectively. CONCLUSIONS: Healthy subjects and ICD patients have distinct TWA profiles. The new TWA profile representation (in amplitude-heart rate pairs) may help comparison among different research protocols.

Electrocardiographic alterations during endosseous implant placement performed with local anesthetic agents.

PURPOSE: The purpose of this study was to analyze electrocardiographic alterations during dental implant surgeries when local anesthetic agents were used. MATERIALS AND METHODS: Twenty implants were placed in 18 healthy patients. An electrocardiogram and Wincardio software were used to gather recordings from 12 static leads every 2 minutes, continuously record coronary artery (D2) derivations, and automatically measure the following electrocardiographic parameters: heart rate, duration and amplitude of the P wave, PR segment duration, ST segment deviation, QRS complex duration, and duration of the RR, QT, and corrected QT (QTc) intervals. RESULTS: Analysis of variance of the values obtained at the different stages showed significant differences (P<.05) for the heart rate and for the duration of the RR and QT intervals. The heart rate increased during the anesthesia, incision, and bone drilling stages, reaching a peak during drilling. Duration of the RR and QT intervals decreased during the incision and drilling stages. Among the electrocardiographic parameters individually assessed, several altered values were found for the duration of the P wave, the QRS complex, and the QT and QTc intervals. Sinusal tachycardia and bradycardia, sinusal arrhythmia, supraventricular extrasystole, ventricular extrasystole, and T-wave inversion were detected. CONCLUSION: Dental implant placement surgery may induce electrocardiographic alterations. The most frequently found arrhythmias were extrasystole and sinusal tachycardia. The anesthesia, incision, and bone drilling stages exhibited the highest heart rate values and the shortest durations of the RR and QT intervals.

Applicability of the Electro-Vectorcardiogram in Current Clinical Practice.

The electrocardiogram (ECG) has been reinvigorated by the identification of electrical alterations that were not definitely clarified before. In this context, and mainly regarding the definition of arrhythmogenic substrates, the association of the ECG with the vectorcardiogram (VCG) has gathered much more information about the cardiac electrical phenomena, thus allowing us to differentiate potentially fatal cases from benign ones. Obtaining a VCG concomitantly with the performance of an ECG has led to a significant gain in the definition of extremely sophisticated pathologies, which function suffer some type of structural or dynamic alterations, involving either the reduction or enhancement of ionic channels and currents. The classic aspects of the ECG/VCG association in the differential diagnosis of myocardial infarctions, conduction disorders, atrial and ventricular hypertrophies, and the correlations between these electrical disorders are still valid and assertive. The association of these pathologies is further clarified when they are seen through the ECG/VCG dyad. The three-dimensional spatial orientation of both the atrial and the ventricular activity provides a far more complete observation tool than the ECG linear form. The modern analysis of the ECG and its respective VCG, simultaneously obtained by the recent technique called electro-vectorcardiogram (ECG/VCG), brought a significant gain for the differential diagnosis of some pathologies. Therefore, we illustrate how this type of analysis can elucidate some of the most important diagnoses found in our daily clinical practice as cardiologists.

Is It Safe for Patients With Cardiac Channelopathies to Undergo Routine Dental Care? Experience From a Single-Center Study.

Background Brugada syndrome and long-QT syndrome may account for at least one third of unexplained sudden cardiac deaths. Dental care in patients with cardiac channelopathies is challenging because of the potential risk of life-threatening events. We hypothesized that the use of local dental anesthesia with lidocaine with and without epinephrine is safe and does not result in life-threatening arrhythmias in patients with channelopathies. Methods and Results We performed a randomized, double-blind pilot trial comparing the use of 2% lidocaine without a vasoconstrictor and with 1:100 000 epinephrine in 2 sessions of restorative dental treatment with a washout period of 7 days (crossover trial). Twenty-eight-hour Holter monitoring was performed, and 12-lead electrocardiography, digital sphygmomanometry, and anxiety scale assessments were also conducted at 3 time points. Fifty-six dental procedures were performed in 28 patients (18 women, 10 men) with cardiac channelopathies: 16 (57.1%) had long-QT syndrome, and 12 (42.9%) had Brugada syndrome; 11 (39.3%) of patients had an implantable defibrillator. The mean age was 45.9±15.9 years. The maximum heart rate increased after the use of epinephrine during the anesthesia period from 82.1 to 85.8 beats per minute (P=0.008). In patients with long-QT syndrome, the median corrected QT was higher, from 450.1 to 465.4 ms (P=0.009) at the end of anesthesia in patients in whom epinephrine was used. The other measurements showed no statistically significant differences. No life-threatening arrhythmias occurred during dental treatment. Conclusions The use of local dental anesthesia with lidocaine, regardless of the use of a vasoconstrictor, did not result in life-threatening arrhythmias and appears to be safe in stable patients with cardiac channelopathies. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT03182777.

Avaliação Prognóstica da Microalternância da onda T na Cardiomiopatia Hipertrófica em um Seguimento Clínico de 9 anos / Prognostic Evaluation of Microvolt T-Wave Alternans in Hypertrophic Cardiomyopathy: 9-year Clinical Follow-up

Resumo Fundamento: A morte súbita cardíaca (MSC), decorrente de arritmias ventriculares, é a principal complicação da cardiomiopatia hipertrófica (CMH). A microalternância da onda T (MAOT) está associada à ocorrência de arritmias ventriculares em diversas cardiopatias, mas seu papel na CMH permanece incerto. Objetivo: Avaliar associação da MAOT com a ocorrência de MSC ou arritmias ventriculares malignas em pacientes com CMH. Método: Pacientes com diagnóstico de CMH e classe funcional I-II (NYHA) foram selecionados de forma consecutiva. No início do seguimento os participantes realizaram a avaliação da MAOT pela metodologia da média móvel modificada no teste de esforço. Os resultados foram classificados em alterado ou normal. O desfecho foi composto por MSC, fibrilação ventricular, taquicardia ventricular sustentada (TVS) e terapia apropriada do cardioversor desfibrilador implantável (CDI). O nível de significância estatística foi de 5%. Resultados: Um total de 132 pacientes (idade média de 39,5±12,6 anos) foram incluídos, com tempo de seguimento médio de 9,5 anos. A MAOT foi alterada em 74 (56%) participantes e normal em 58 (44%). Durante o seguimento, nove (6,8%) desfechos ocorreram, com prevalência de 1,0%/ano, sendo seis casos de MSC, dois choques apropriados do CDI e um episódio de TVS. MAOT alterada foi associada à taquicardia ventricular não sustentada no Holter (p=0,016), espessura septal≥30 mm (p<0,001) e resposta inadequada da pressão arterial ao esforço (p=0,046). Cinco pacientes (7%) e quatro pacientes (7%) com MAOT alterada e normal, respectivamente, apresentaram desfecho primário [OR=0,85(IC95%: 0,21-3,35, p=0,83)]. Curvas de eventos de Kaplan-Meir não apresentaram diferenças entre MAOT normal e alterada. Conclusão: A MAOT alterada não foi associada à ocorrência de MSC ou arritmias ventriculares potencialmente fatais em pacientes com CMH, e a baixa taxa desses eventos em um seguimento em longo prazo sugere o bom prognóstico dessa cardiopatia.

Abstract Background: Sudden cardiac death (SCD) resulting from ventricular arrhythmia is the main complication of hypertrophic cardiomyopathy (HCM). Microvolt T-wave alternans (MTWA) is associated with the occurrence of ventricular arrhythmias in several heart diseases, but its role in HCM remains uncertain. Objective: To evaluate the association of MTWA with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients in a long-term follow-up. Methods: Patients diagnosed with HCM and NYHA functional class I-II were consecutively selected. At the beginning of the follow-up, the participants performed the MTWA evaluation using the modified moving average during the stress test. The results were classified as altered or normal. The composite endpoint of SCD, ventricular fibrillation, sustained ventricular tachycardia (SVT) or appropriate implantable cardiac defibrillation (ICD) therapy was assessed. The level of significance was set at 5%. Results: A total of 132 patients (mean age of 39.5 ± 12.6 years) were recruited and followed for a mean of 9.5 years. The MTWA test was altered in 74 (56%) participants and normal in 58 (44%). Nine events (6.8%) occurred during the follow-up, with a prevalence of 1.0%/year - six SCDs, two appropriate ICD shocks and one episode of (SVT). Altered MTWA was associated with non-sustained ventricular tachycardia on Holter (p = 0.016), septal thickness ≥30 mm (p < 0.001) and inadequate blood pressure response to effort (p = 0.046). Five patients with altered MTWA (7%) and four patients with normal MTWA (7%) had the primary outcome [OR = 0.85 (95% CI: 0.21 - 3.35, p=0.83)]. Kaplan-Meir event curves showed no differences between normal and altered MTWA. Conclusion: Altered MTWA was not associated with the occurrence of SCD or potentially fatal ventricular arrhythmias in HCM patients, and the low rate of these events during long-term follow-up suggests the good prognosis of this heart disease.

Favorable Safety Experience of Local Dental Anesthesia in ICD Recipients with Cardiac Channelopathies

Abstract Background Dental anesthetic management in implantable cardioverter defibrillator (ICD) recipients with cardiac channelopathies (CCh) can be challenging due to the potential risk of life-threatening arrhythmias and appropriate ICD therapies during procedural time. Objectives The present study assessed the hypothesis that the use of local dental anesthesia with 2% lidocaine with 1:100,000 epinephrine or without a vasoconstrictor can be safe in selected ICD and CCh patients, not resulting in life-threatening events (LTE). Methods Restorative dental treatment under local dental anesthesia was made in two sessions, with a wash-out period of 7 days (cross-over trial), conducting with a 28h - Holter monitoring, and 12-lead electrocardiography, digital sphygmomanometry, and anxiety scale assessments in 3 time periods. Statistical analysis carried out the paired Student's t test and the Wilcoxon signed-rank test. In all cases, a significance level of 5% was adopted. All patients were in stable condition with no recent events before dental care. Results Twenty-four consecutive procedures were performed in 12 patients (9 women, 3 men) with CCh and ICD: 7 (58.3%) had long QT syndrome (LQTS), 4 (33.3%) Brugada syndrome (BrS), and 1 (8.3%) Catecholaminergic polymorphic ventricular tachycardia (CPVT). Holter analysis showed no increased heart rate (HR) or sustained arrhythmias. Blood pressure (BP), electrocardiographic changes and anxiety measurement showed no statistically significant differences. No LTE occurred during dental treatment, regardless of the type of anesthesia. Conclusion Lidocaine administration, with or without epinephrine, can be safely used in selected CCh-ICD patients without LTE. These preliminary findings need to be confirmed in a larger population with ICD and CCh.